The present invention relates to capillary splices for optical fibers, the method of making such splices, and the method of splicing optical fibers together; and more particularly to an economic method of making capillary splices for optical fibers and the resulting article.
Optical fibers, such as optical waveguides, have a glass core and a cladding surrounding the core having a refractive index less than that of the core material. Some optical fiber systems require splices such that at least a portion of the energy propagating in one fiber may be transmitted to at least one other fiber.
Optical fibers may be single-mode where the core diameter is of just one or a few microns or multi-mode fibers having core diameters significantly larger.
An elastomeric fiber optic splice is described in U.S. Pat. No. 4,257,674. This fiber optic splice has a fiber receiving member formed in a pair of sections such that, when assembled, it provides an external polygonal shaped surface. These sections have complimentary and mating planar surfaces in engagement with one another One of the planar surfaces has an axially aligned V-shaped groove formed therein facing the other of the planar surfaces thereby forming an opening therebetween. The fiber receiving member is formed of an elastomeric material of sufficient resilience to permit the groove opening to expandably receive optical fibers dimensioned larger than the opening. A cylindrically shaped sleeve is disposed about the elastomeric receiving member surrounding the polygonal shaped surface and holding the two sections of the member in an assembled relationship. As fibers are inserted into the groove, they are maintained in place by the resilient properties of the two piece elastomer member.
Another optical fiber splice is the Norland self aligning UV curable splice and the Lightlinker fiber optic splice system. These splices include a central glass alignment guide composed of four tiny glass rods which have been fused together to provide a hollow core containing four V-grooves at the fused tangential points The ends of the guide are bent somewhat along the longitudinal axis. This forms a fiber deflecting elbow on either side of a straight central portion of the guide. When fibers are inserted into the guide, the upward or downward slope of the ends forces the fibers to orient themselves in the uppermost or lowermost V-grooves of the guide, respectively. When the fibers meet at the center portion, they are both tangent to the guide surfaces so that the ends thereof abut each other. The splice is used by first filling the central opening with a UV curing optical adhesive. After the fibers are prepared by stripping any exterior resin coating and squaring of the ends, they are inserted into the splice so as to be aligned when they contact each other. Exposure to UV light cures the adhesive encapsulating the fiber providing handling strength.
Some of the problems and disadvantages with prior art splices are the complexity and cost thereof. Such splices require assembling various components and fusing them together. Alternatively, the splices are made of elastomeric material which may be less stable chemically and has a high expansion. Prior art splices are simply more complicated to assemble, use and manufacture. In addition, many of the prior art fabrication steps are highly labor intensive and, therefore, add greatly to the cost of the splice.
For teaching of forming optical waveguides or other optical fibers reference is hereby made to U.S. Pat. No. 3,659,915 to R. D. Maurer and P. C. Schultz, U.S. Pat. No. 3,711,262 to D. B. Keck and P. C. Schultz, U.S. Pat. No. 3,737,292 to D. B. Keck, P. C. Schultz and F. Zimar, U.S. Pat. No. 3,737,293 to R. D. Maurer, U.S. Pat. No. 3,775,075 to D. B. Keck and R. D. Maurer, U.S. Pat. No. 3,806,570 to J. S. Flamenbaum, P. C. Schultz, and F. W. Voorhees, U.S. Pat. No. 3,859,073 to P. C. Schultz, and U.S. Pat. No. 3,884,550 to R. D. Maurer and P. C. Schultz.